1. Field of Invention
The present invention is a novel urethral plug which can be inserted into the urethra to restrict the flow of urine through the urethra and is used by a person suffering from urinary incontinence. This device can be used by male or female patients.
2. Prior Art
Urinary stress incontinence is defined as the involuntary loss of urine when the pressure within the urethra exceeds the maximum urethral pressure in the absence of detrusor activity.
While the problem of stress incontinence occurs in both men and women, it predominantly occurs in women of childbearing age and beyond. The frequency of incontinence in women is approximately four times that of men. Less than one-third of women with moderate to severe incontinence are treated for the problem. While 25 to 41% of all women suffer some form of incontinence, 6 to 8% are troubled by the problem to the extent that they must wear diapers or sanitary napkins constantly.
There are in existence many methods and devices used to address the problem in involuntary loss of urine in people suffering from incontinence. Surgery is perhaps the most desirable method in cases of severe incontinence in younger patients. The surgical alternative often involves a procedure whereby the neck of the bladder is reduced by suspending the bladder. However, there are numerous well known risks associated with this as well as any surgical procedure. For some patients, surgery is not recommended for medical or other reasons, and for those with mild incontinence surgery is not an appropriate solution. The expense of surgery is also a factor to be considered.
Incontinence can also be treated with various medications as well as exercises. These methods vary depending whether the patient is male or female. The most commonly used device for both sexes is the diaper which simply catches and absorbs the urine involuntarily voided. This device obviously does not alleviate the problem of incontinence and has many hygienic and aesthetic drawbacks. Leakage occurs frequently, and there is no control over the voiding of urine. For women, rigid devices, such as tampons, were suggested. Such rigid devices must be inserted into the vagina to support the urethra. These types of rigid devices are difficult to fit and thus require medical assistance in fitting. There are also in existence prosthetic urethral valves, which require surgical implantation and invite numerous complications. Foley drainage catheters and drainage bags are also known, but these devices have many disadvantages.
The following discussion addresses the problems with devices taught by prior art.
U.S. Pat. No. 4,457,299 to Corewell teaches an internally prestressed capsule device which is inserted into the urethra. This device can be used by both men and women. The prestressed capsule deforms the lower interior of the urethra into a broadly elliptical shape, and the capsule is set at a prestressed pressure slightly above the involuntary pressure. When the urine pressure exceeds the preset pressure of the capsule, the capsule deforms allowing the urine to flow around the device. When voiding ceases, the device returns to its prestressed position and configuration. As an indwelling device, the device faces the problems of encrustation and infection. Also, no mechanism for anchoring the device in place is described, and it is not clear that one could anchor a device such as this in place, seal off the urine and leave the urethra unharmed. In addition, there is a need to measure the diameter of the patient's urethra and perform pressure testing before this device can be used.
U.S. Pat. No. 4,553,533 to Leighton teaches a prosthetic urethral sphincter valve which is placed in the urethra and anchored in the bladder. The valve is composed of a spring, an annular guide, a diaphragm and a grease filled bag member. The patient increases his bladder pressure by means of a valsalva maneuver, and holds this pressure while the valve activates. The urine passes through the valve, and then the spring returns to its collapsed position when the bladder pressure is released. This device is relatively expensive and complicated, requiring that it be used for a relatively long time in order to make it economically feasible. It appears that this device would be uncomfortable for the patient. Furthermore, no means for anchoring the device to prevent its migration into the bladder is provided. As an indwelling device, it is subject to infection, encrustation and irritation. Due to the complexity and location of the device, it must be inserted under the guidance of a physician.
In somewhat unrelated art but art of interest, U.S. Pat. No. 4,682,592 to Thoregard describes a device which achieves reversible male sterilization. This device is a hollow elongated tube with an expandable elastic cap forming a fluid tight seal at one end and a plug which forms a seal on the other end. In one embodiment, the device is inserted though the urethra to temporarily block the passage of sperm. In the second embodiment, a smaller plug is inserted into the juncture of ejaculatory ducts with the urethra or into the vas deferens. The second embodiment requires implantation by a physician. The device described by Thoregard never gets near the bladder neck or the bladder.
International Patent Application No. PCT/GB88/00464 to Prosthex, Ltd., teaches an incontinence device for use by women. This device is a sponge tampon which is inserted into the vagina. This device is supposed to exert pressure on the urethra, but it does not prevent involuntary voiding. It does not stop or plug the urethral opening.
Nielsen, Kurt K. et al, "The Urethral Plug: A New Treatment Modality for Genuine Urinary Stress Incontinence in Women", J. Urology, Vol. 44, p. 1199 (1990). This paper describes a device to be used by women which consists of one or two solid spheres of 7 mm in diameter, located along a 3 mm soft shaft. A thin and soft plate is used to anchor the device at the meatus urinarius or the opening of the urethra. The meatal plate is located normal to the end of the device to prevent the plug from being drawn into the urethra. One sphere is located upstream of the maximum urethral closing pressure point, corresponding to the location of the sphincter. In the two sphere embodiment, the second sphere is located with its midpoint at the bladder neck, and is used to assist in reducing urinary flow and pressure transmission to the urethra that the sphincter can operate. When the patient wants to void, the plug is removed and then a new one inserted.
One problem with this device is that the patient must have three urethral closure pressure profiles performed before the device is inserted in addition to various other examinations. This is done in order to locate the urinary sphincter. The device is then custom made for each patient based on the profiles and according to their anatomy. This device is made from Kraton G, a non-toxic thermoplastic elastomer. Additional problems were associated with the use of this device. Patients often lost the plug showing inadequate anchoring. Some could not learn how to insert it and there were difficulties with the placement of the distal sphere. In addition, there is no sealing mechanism to prevent urine outflow, so that the device must depend on the body's own sealing mechanism. This presents a problem, because there is a significant population without such capabilities.
The devices and methods described above present many unsolved problems and various drawbacks. Thus, a great need exists for a device and method for treating urinary incontinence in both men and women.